Development of Class Library for Fluid-Structure Interaction

流固耦合问题仍然是未知的现象，人们期待通过数值模拟来研究流固耦合问题。本研究开发了C++程序设计语言类库，用于分析流固耦合问题。该库由具有复杂数值方法的流体模拟类、结构分析类、流固耦合类、网格生成类、并行计算类和可视化类组成。在流体模拟类中，开发了高精度的数值方法，并提出了易于引入流固耦合的网格上的稳定耦合方法。该方法也易于并行计算，爆炸模拟是在PC机群系统的2000CPU上进行的。在AMR子类中，可以以三阶空间精度细化树数据结构的网格。结果表明，重叠网格子类对于刚体在流体中的变换和旋转运动是非常有效的。利用这个子类对风力机的扭矩进行了研究。我们发展了浸没边界方法的子类，使得在笛卡尔网格上处理复杂形状成为可能。采用离散单元法的子类方法研究了质量-弹簧模型结构的破坏问题。真实感绘制子类可以可视化气泡流动和中尺度台风模拟，并使用POV-Ray软件制作高质量的动画。这些都得到了高度评价。

Fluid-structure interaction problems are still unknown phenomena and it is highly expected to study them by numerical simulations. In this study, the class library of C++ programming language was developed to analyze fluid-structure interaction problems. The library consists of fluid-simulation class with sophisticated numerical method, structure-analysis class, fluid-structure coupling class, grid generation class, parallel computing class, and visualization class. By combining these classes depending on the problems, numerical simulation codes are easily constructed.In the fluid-simulation class, high-accurate numerical method was developed and the stable coupling method on the collocated grid was proposed in which easily introduces fluid-structure interaction. This method is also easily applicable to parallel computing and the explosion simulation was executed by 2000 CPU of a PC-Cluster system. In the AMR sub-class, it is possible to refine the mesh of the tree-data structure with third-order spatial accuracy. It is found that the overset grid sub-class is quit effective for rigid body of transform and rotational motion in fluid. The torque of the wind turbine was studied with using this sub-class. We developed the sub-class of Immersed boundary method which makes it possible to treat complex shapes on Cartesian grid. The sub-class of Distinct Element Method was used to study destruction of the structure with mass-spring model. The sub-class of photo-realistic rendering could visualize the bubbly flow and meso-scale typhoon simulation and made high-quality animations by using POV-Ray software. These ware highly evaluated.